since when can a company policy trump a constitutional right?
While I am definitely in favour of gun rights (in fact, I pretty much think that the term "reasonable restriction" is an oxymoron, where 2nd amendment rights are concerned), let's also not forget that the Bill of Rights applies to government interference with the natural rights of the citizens. It doesn't apply on private property or private space. While I think it's idiotic for a company to prevent its law-abiding workers from carrying onsite (especially if they have a CCW and its in a locked vehicle), that is also the company's choice, as a private entity.
If a moonbat comes onto your front lawn and wants to hold an assembly in support of some political position diametrically opposed to your own, are you violating their 1st amendment rights to free speech and free assembly if you run them off? No, of course not, since the Constitution doesn't apply to the exercise of one person's rights on another person's property, if the other person has said they can't.